1. Field of the Invention
The present invention generally relates to a motor with thrust bearing and, more particularly, to a motor of simple structure and easy to be assembled.
2. Description of the Related Art
Referring to FIG. 1, a sketch diagram of a conventional motor with a thrust bearing is shown, which is identified with a reference number of “9” and which has a seat 91, a stator 92 and a rotor 93. The seat 91 couples with a bearing housing 911 receiving a thrust bearing 912 and a pushing board 913 inside. The bearing housing 911 has two opposite openings for the rotor 93 to extend into the thrust bearing 912 and to couple with a lid 914 respectively. The stator 92 couples with an outer periphery of the seat 91. The rotor 93 includes a hub 931 integrally forming an annular wall 932 and a shaft 933. The annular wall 932 is positioned between the seat 91 and the bearing housing 911, to provide functions such as dust-resistance and anti-leakage of oil. The shaft 933 extends through the thrust bearing 912 and couples with the pushing board 913. Specifically, this kind of motor 9 is disclosed in patents such as a China patent application with the application number of 200410054614.4 and title of “Liquid Hydrodynamic Bearing, Main Shaft Motor, Method for Producing Rotor Assembly Recording Disc Driving Apparatus.”
With the above structure, this motor 9 has to be assembled by a specific order. First, the thrust bearing 912 is inserted into the bearing housing 911. Second, the shaft 933 and the pushing board 913 are coupled to the thrust bearing 912 via the opposite openings of the bearing housing 911, with a free end of the shaft 933 fixed to the pushing board 913, to avoid disengagement of the rotor 93 from the bearing housing 911 by an axial limitation of the pushing board 913 relative to the thrust bearing 912. Finally, the lid 914 is coupled to cover one of the two openings of the bearing housing 911 and is opposite to the rotor 93. It is apparent that the above steps for assembly of the motor 9 are complex. Besides, since the connection between the shaft 933 and the pushing board 913 is inside the thrust bearing 912, it is also difficult to perform this connection smoothly.
Furthermore, it is necessary for the bearing housing 911 to have the opposite openings in order to perform the above assembly steps. This arrangement not only leads to an additional need in the lid 914 to cover the opening opposite to the rotor 93, but also results in leakage of the oil inside the thrust bearing 912 via a gap between the lid 914 and the edge of the opening.
Therefore, the conventional motor 9 has problems such as bad oil-preservation, high operation noise caused by oil-leakage, high cost of manufacture, and short lifetime. As a result, it is necessary to improve the conventional motor 9.